Answer;
The chemical energy in food is converted to potential energy stored in the body which is then converted to mechanical and kinetic energy, as a result of motion while running then to heat energy.
Step-by-step explanation;
The energy bar eaten by Sheila has chemical energy locked up inside it. This chemical energy is converted to mechanical energy in form of potential and kinetic energy and this in turn is converted to heat energy as the run progresses. Thus, the energy changes are: chemical energy to mechanical energy [kinetic and potential] and finally to heat energy.